There are shoes whose shoe upper is waterproof and water-vapor permeable because it is lined with a functional layer. A shoe upper of this type remains breathable in spite of being waterproof. Special efforts are required to ensure permanent waterproofness in the region between the end of the upper on the sole side and the sole construction.
To achieve this, sock-like inserts, also known among those skilled in the art as bootees, have been used between the upper and the sole construction on the one hand and an inner lining on the other hand. Since such bootees are shaped by fusing together cut-to-size parts, they need not have any stitching holes. However, the use of bootees is quite costly in production if the bootees are to correspond to some extent to the shape of the respective shoe.
Another known method is to use outsole material of a molded-on outsole to seal the lower region of the shoe construction, and consequently the lower region of the upper lined with the functional layer and possibly sewn to an insole. This cannot, however, prevent water from reaching the end of the upper on the sole side, and consequently the end of the functional layer on the sole side, on the outer material of the upper, which generally conducts water by capillary effects, and consequently reaching the generally very strongly water-absorbent inner lining located on the inner side of the functional layer, via water bridges, in particular in the form of textile fibers at the cut edge of the end of the upper on the sole side.
These problems have been overcome by a sole construction known from EP 0 298 360 B1, in which the functional layer has in the region of the end of the upper on the sole side an overhang with respect to the outer material, which is bridged by a gauze strip, of which one side is securely sewn to the outer material and the other side is securely sewn to the functional layer and to the insole. In this case, the overhang of the functional layer is sealed by the outsole material which has penetrated through the gauze strip during the molding-on, when it is liquid. The gauze strip represents a barrier to water which has penetrated along the outer material to under the region of the end of the upper on the sole side covered by the outsole, in particular if it is a monofilament gauze strip, so that such water cannot penetrate as far as the cut edge of the functional layer on the sole side and consequently not as far as the inner lining of the footwear.
This gauze strip solution has proven to be extremely successful. Since in this case the sealing of the end region of the functional layer on the sole side requires the molding-on of an outsole, this known method is restricted to shoes with a molded-on outsole and cannot be used for shoes with a cemented-on outsole. Consequently, it is also not available for shoes of a more elegant style. The molding-on of outsoles entails high costs, which lead to a long payback period and make it necessary to produce the respective type and size of shoe in large numbers.
DE-A-38 40 263 discloses a similar shoe construction in which an overhang of an end of a functional layer on the outsole side protruding with respect to an end of the outer material on the outsole side is bridged by a sealing strip, in which the strip is a textile strip which has a polyurethane coating on one or both sides and is intended to bring about a sealing connection between the functional layer overhang and an edge of a moulded-on outsole covering the sealing strip. This solution is also restricted to shoes with a moulded-on outsole.
WO-A-9641548 discloses footwear with a moulded-on outsole in which an outer-material end region on the outsole side is folded over outward and an functional-layer-lining end region on the outsole side is folded over inward, the outer-material end region which is folded over folded over outward being securely sewn on a frame-shaped first insole and the functional-layer-lining end region which is folded over inward being arranged between the first insole and a second insole, located above the functional-layer-lining end region. The functional-layer-lining end region is adhesively bonded to the second insole by means of a sealing compound or adhesive tape coated with polyurethane hot-melt adhesive and to the second insole by means of an adhesive of a type not specified any more precisely.
Shoe constructions in which the functional layer likewise has an overhang beyond the outer material in the end region on the sole side, but in which there is no gauze strip, are likewise known. In this case, the outsole material is molded directly onto the functional layer in the region of the overhang. This method is also suitable only for footwear with a molded-on outsole.